SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74391b4b444a73dfe0ee0b1b057bdb2ff5fe02fecc4c16b220b5ed79327f1b22' 
  AND token = 'sVwHB9+YHaaUINMHV+6Hfr4sfU1QoO3Z8LQ+rrmek0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}